The invention relates to a device for controlling an actuator, in particular, for controlling an internal combustion engine.
A known actuator (DE 195 26 683 A1) has an actuating element, designed as a gas exchange valve, and an actuating drive. The actuating drive has two electromagnets between which, in each case counter to the force of a restoring means, an armature plate can be moved by switching off the coil current at the holding electromagnets and switching on the coil current at the capturing electromagnet. The coil current of the respective capturing electromagnet is regulated to a predetermined capture value, to be precise during a predetermined period of time which is dimensioned such that the armature plate strikes a bearing surface on the capturing electromagnet within the period of time. The coil current of the capturing electromagnet is subsequently regulated to a holding value.
The force acting on the armature plate essentially depends on the position of the armature plate and the excitation of the coil of the respective capturing electromagnet. The excitation of the coil depends, in turn, on the current through the coil. The gradient of the current rise of the current through the coil is given by the voltage drop across the coil.
Motor vehicles usually have a voltage supply which makes a predetermined operating voltage available to the electrical loads of the motor vehicle. At the customary operating voltages of from 12 to a maximum of 42 volts, an undesirable fallback of the armature plate to a rest position can thus occur. Likewise, if appropriate, the point in time of xe2x80x9cgas exchange valve openxe2x80x9d or xe2x80x9cgas exchange valve closedxe2x80x9d cannot be set sufficiently accurately.
DE 197 01 471 A1 discloses an apparatus for driving an electromagnetic load, with a capacitor which is discharged in each case at the beginning of load driving. This leads to a high current rise in the electromagnetic load.
Furthermore, DE 44 13 240 A1 discloses an apparatus for driving an electromagnetic load which comprises a half-bridge and an energy-storing element arranged between the half-bridge and a voltage source.
In one embodiment of the invention there is a device for controlling an actuator which is simple and ensures certain and reliable operation of the actuator.